- Top fuel dragsters make over 10,000 horsepower.
(engine revving) That is an insane amount of power. One top fuel dragster's
engine makes more horsepower than 10 Formula 1 cars, 14 NASCAR cup cars and an infinite number of
current condition low cars! (engine humming)
(sad music) - No! - How about a joke.
(Jeremiah clicking) - They are tuned to be so powerful that their pistons, rings,
connecting rods, spark plugs only last one run down the drag strip. That's under a mere four seconds of use and if they push further than that. (explosion) Your average car engine can
last over 3000 hours of runtime. That's 3 million times
longer than these dragsters. So what's the difference? What's inside a top fuel
engine that's so different from your mom's minivan? What allows them to
make so much horsepower but last such a limited amount of time, and what's the sequence
of events that leads up to their failure? Well today on "B2B," we're
going to snap some necks. (bones crunching)
(laughter) - Canan help me. (laughs) Help me! (upbeat music playing) Thanks to Keeps for
sponsoring this episode. When I was a kid, I was afraid of swimming because my mom told me man-eating sharks lived in these waters, but now that I'm 42, I'm realizing my mommy just
wanted this nice swimming hole all to herself, ain't the right Dave? (bird squawking) - [Ma] Jeremy, your doctor's on the phone! - Tell him I'm busy ma! - [Ma] Okay, okay. And take your hat off, the
sharks are going to ruin it. - Okay, very funny mama Jerry. If I take off my hat, my head's going to turn into a lobster. If only I wasn't one of
the two out of three guys to experience some sort
of male pattern baldness by the time I was 35. (bird squawking) Yeah, I know Dave! Captain obvious over here. Keeps makes hair loss prevention easy by giving you access
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(piano music) Top fuel dragster drivers
experience more Gs than an astronaut headed
to frigging space, and if you want to accelerate that fast, you need power, loads and loads of power. At the heart of these cars
are big 500 cubic inch V8s. The architecture or the block comes from the 1964 Chrysler
Hemi Elephant race motor. Well, unlike the iron blocks
used back in those days these engines are made
from billet aluminum. They use a two-valve
hemispherical combustion chamber that's also made from billet aluminum. The hemispherical head
design holds onto the heat produced by combustion
better than a non-Hemi head, which allows for a more
complete combustion of your air fuel mixture. You also get to use big old fat valves. Bigger valves allow for
more air to get drawn into the cylinders and more
exhaust to get dumped out. When you can add more air,
you can add more fuel, which means you can make- - Full power? You're god dang right more power! Well pump (indistinct). - But even a 500 cubic
inch motor with flowy heads needs some help in its quest
to make 10,000 horsepower, and that help comes in the
form of a supercharger. But not just any old supercharger, oh no. Top fuel dragsters use a
version of a root style blower that has the ability to spin
up to 12,000 revs per minute making 60 pounds of intake pressure. The amount of horsepower
just to spin the pulley of this supercharger is
right at 750 horsepower. That is a lot of parasitic loss. But with that loss comes
a lot of pressurized air, 3000 cubic feet of air
per minute gets forced into the cylinders. There's an actual pressure
bomb on top of these engines, and because of that, they
use Kevlar bags wrapped around the supercharger to keep
it contained if it blows up. And when you take all that
air from the supercharger and add it to the 1.2
gallons of nitromethane being delivered per second, the combo of air fuels compress
into an almost solid mixture before ignition. Nitromethane is a fuel
choice for a few reasons. Nitromethane or CH3NO2 is
a mono propellant fuel, which means it can combust without any additional air required. That's because it carries its own oxygen therefore needing less
atmospheric air coming into the cylinders from the intake. Now for gas engines, the ideal air to fuel ratio is 14.7/1. Meaning for every one part
gas, you need 14.7 parts air. But since nitromethane
has its own oxygen source, it can burn at a ratio of 1.7/1. This means you can squirt
in a lot more nitromethane into your cylinders,
approximately 8.7 times more. On paper, nitromethane is
less energetic than gasoline but like I said, you can
burn a lot more of it. Gasoline, it has about four
times more heating value than nitromethane. You get 19,000 BTUs per pound for gas, while nitro just has under
5,000 BTUs per pound. But that doesn't take into account the fuel's specific energy. Specific energy, it's the
amount of energy per unit mass. So if we divide the heat value
by the air to fuel ratio, it tells us how much
heat energy is delivered per pound of air into the motor. Nitro's specific energy
value is 2.2 times greater meaning these engines
make 2.2 times more power by just using this fuel alone. Now, the other reason
for using nitromethane is it cools the engine. The centers of the bores
on these blocks are defined by the NHRA rule book. So to get the maximum
displacement of 500 cubic inches, the water jackets are
removed from the block. The only thing that's
keeping these engines cool is the fuel itself. There's no radiators. And remember we can use
8.7 times more fuel, which means we get 870% more cooling from the fuel's vaporization
that's happening inside the cylinders. And also, it produces less heat
like we talked about before. So by combining these two factors your net cooling effect is 2000% more for a set amount of engine horsepower. Now making sure that
engine doesn't hydro lock all that nitromethane is
the job of the spark plugs. If you don't spark that air
fuel mixture in the cylinder, it'll blow the cylinder heads clean off. Kind of like what happens
if someone doesn't feed me in the morning. (flames burst)
I get angry! So these dragsters use two
spark plugs per cylinder powered by dual magnetos, and those magnetos produce
44 amps to each cylinder. That's right in the ballpark of the current needed for an arc welder. By the time the car gets
up to 300 miles per hour, the spark plugs are literally burned away due to the amount of heat being generated. This leaves certain cylinders dieseling, meaning the compression plus
the 1400 degree exhaust valves is what's causing ignition. But really, many of the
cylinders aren't even firing. If you watch one of these
cars run down a strip, look at the color of the
flame leaving the exhaust. If it's a bright yellowish orange, the cylinder is still firing. If it's white, that cylinder is dieseling. The only way that these
engines can now be shut off is if it runs out of fuel or it blows up. I hope you're starting to realize why these engines only last
the amount of time they do. They are making a lot,
a lot of horsepower. But how do you get that
horsepower from the engine to the ground? What kind of transmission
can handle all that torque being generated by these engines? That's a great question. No transmission! Top fuel cars run a direct drive with a centrifugal clutch, and how those clutches
work is pretty amazing. Now I'm going to explain how a clutch in a motorcycle works first because it's a bit easier to understand, and these clutches operate very similar to how a motorcycle clutch works. Now in a motorcycle, the
function of the clutch is to connect the primary
gear coming off the crank to the transmission,
and it works like this. So you have right here,
this is an outer basket and then inside it you
have an inner basket, and in between these two you
have a series of metal discs and friction plates. This is your clutch pack and they connect these
two baskets together. These metal discs right here, they have tabs that latch into
the inner basket like this. Now these friction plates, they have outer tabs that
latch onto the outer basket. Now you can move the outer basket independent from the inner basket, but when I apply pressure to these plates, they grab each other and
they spin as one whole unit. That pressure comes
from the pressure plate, which sits on top of it like
this and some external springs. Now because the outer basket is connected to the primary gear and the inner basket is
connected to the transmission, when the clutch is engaged,
you get forward movement. Now, when you pull on your clutch lever, you pull these two baskets apart and now they can spin freely,
they're no longer connected. Motorcycle clutch 101. Now who wants to see a
two-wheeled show here at "Donut"? I do. I do. James, let me do it please. So how does a motorcycle
clutch like this compare to a top fuel dragster's clutch? Well, instead of a clutch lever used to operate the clutch pack, these centrifugal clutches
use a series of levers and a throwout bearing to
engage the clutch pack. Similar to our basket in our motorcycle, We have a flywheel, clutch disc, floating plates and a
type of pressure plate. Now stacked inside of that
flywheel are six clutch discs and five floaters. And at the very end of that flywheel is the coolest part of the clutch, and that's the clutch hat. It has a series of small
levers and they look like bent little fingers, and those fingers are
responsible for pushing up against your clutch pack. This one has 18 levers, six primary ones and 12 secondary ones. And as the engine RPM rises
from 2,500 RPM to 8,500 RPM, these levers swing outward and
begin pushing on the plate. Those levers are released
by the throwout bearing in the clutch control system. Now once the secondary fingers
are pushing the pack together the clutch pack is fully engaged and the connection between
the engine and the rear end is complete. So instead of using gears, these cars gradually slip the clutch. It'd be the same thing
as if you were starting your manual car in third or fourth gear and then slowly releasing the clutch until you build up enough speed. The only difference is
that slow release happens in under four seconds in these cars. What's even crazier is that
unlike a motorcycle clutch, which is bathed in oil,
Ducati bikes excluded here, these plates are exposed to air. Now without oil, you can
generate more friction, which in turn gives you
more clamping force. The downside of that is it
generates a lot of heat. The clutch pack spikes to
3,700 degrees Fahrenheit during the first few tenths of the run. That's enough heat that these discs end up welding themselves together. These engines are always
on the verge of disaster. So what happens when these crazy powerful, crazy expensive engines do blow up? What are the parts that fail? Head gaskets, ugh! Your engine has them and
so to top fuel dragsters. Unlike composite gaskets which use different materials
pressed into one solid gasket, this is probably what's in your car, dragsters use multilayered
steel or MLS head gaskets that are made of multiple
pieces of steel attached at just a few points with rivets. Now these drags are teams, they do some cool stuff
to the outer two layers of an MLS gasket. A bead is rolled or embossed into the steel that
surrounds the cylinder bores. The gasket is compressed but the ceiling beads aren't crushed flat when you bolt the cylinder
heads to the block. These beads are what gives you
an amazing drag-worthy seal. If combustion pressure is so great that it causes the head to
lift off the blocks slightly, those beads will act like a spring and pull everything back so
that the seal is preserved. That said, when you're dealing
with a top fuel dragster that has 10,000 horsepower, things don't always go exactly as planned. So here's what actually goes wrong. Once an MLS gasket is heat cycle, it's embossments will not spring back to where they were originally. And since the embossment
is the sealing area that we talked about before, when that spring action is totally gone, there's a big chance
for a compression leak. Now besides a compression loss, oil retention can also be compromised. There are 12 quarts of oil
keeping this engine all lubed up. If any of that oil gets
shot out of the hood, it can catch fire. Not only that, if you have oil leaking out it's not there to lubricate the piston and the cylinder walls. So you can seize your engine. Now if you're in a major bind at the track and you need to reuse a head
gasket, yeah, you can do it but it's not ideal
compared to the low cost of a gasket and the high risk, teams replace them after every run. They replace a lot of parts. It takes only 40 minutes for
the engine to get rebuilt with new head gasket, pistons, rings, clutch plates, and even rods. And rods, that's the next
component that often fail in these engines. The connecting rods are
the link between the crank and the piston. They aid in taking the linear movement and translating it into
rotational movement. Dragster rods have to be strong enough to withstand the highest combustion loads without bending or
buckling under pressure. With rods having to constantly
resist stretching forces that try to pull them
apart at high engine speed, it's common for structural
overloading to occur if a rod lacks the tensile strength that handles extreme RPM. As the G-forces produced
by dragsters multiply their inertia effects on the piston, the small end of the rod
may be stretched to a point where it fails at or
just below the wrist pin. The inertia of the piston
reciprocating up and down exponentially increases
the effective weight of a piston as your RPMs go up. The force generated by a
piston hitting top dead center at 1000 RPM is 50 times its initial weight when the engine is turned off. At 10,000 RPM, the effective
weight of that same piston is 5,000 times greater. That's a lot of force stretching the rods, and stretching them 166
times every single second. Since it's so easy for
things to go horribly wrong with the connecting rod, they have a very short
service life in racing. (country music playing) ♪ Saddle up, set your spurs on down ♪ ♪ Donut's made the sickest hat in town ♪ ♪ License Realtree camo on your head ♪ ♪ Yeah, that's what I said ♪ ♪ Sing it ♪ ♪ C-A-M-O H-A-T ♪ ♪ Baddest hat that you can see ♪ ♪ C-A-M-O H-A-T ♪ ♪ Made for you and me ♪ - [Crowd] Woo! - Now you can represent your
favorite automotive brand when you're on the road, on the lake, or up in that (indistinct). Only available at DONUTMEDIAS.COM. Get you one. ♪ Whether you're fixing
cars or in the woods ♪ ♪ Donut's got you looking good ♪ ♪ In your C-A-M-O H-A-T ♪ ♪ Blend in and stand
out in "Donut" country ♪ - So while the mechanics
behind why they fail are pretty complicated, as you've seen, the reason for their short
lifespan are pretty intuitive. Basically it comes down to two things, the way they use their engines and their hyper-specific
super powerful output. These dragsters spend
their entire life running on a wide open throttle at
the top of their rev range. It's constantly running
at its max power output, which is why their life
is such a short one. Thank you guys so much for
watching this episode of "B2B." If you want to see more dragster stuff, and you want us to really get nerdy, really dive deep in there, let us know, put some comments
down below, like this video, follow us here at "Donut"
on Instagram @DONUTMEDIA, follow me @JEREMIAHBURTON and until next week, bye for now.
